[1] Clock drift - Wikipedia, the free encyclopedia ( ()) <https://en.wikipedia.org/wiki/Clock_drift>
Every clock has a value that differs from real time (the best representation of which being International Atomic Time); no clock is perfect. A quartz-based electronic clock keeps imperfect time, but maintains a consistent inaccuracy. This base 'inaccuracy' is known as 'time skew' or 'time drift'.
[3] expand 'clock drift' section in privacy/security (igrigorik著, ) <https://github.com/w3c/hr-time/commit/4f49403c3c2ceb3d9e87a1efd0c3eba5b61c2587>